The so called "light-inlay" or "down lights" is like a housing which provides all necessary connects and junctions for lagging,bulbs,accessories, and even the wall and floor; the down lights structure showed in FIG. 1 is designed by "Concord Lighting Limited" in England, this down lights structure is composed of lamp shell stand, light bulb stand, catoptric lagging, lagging, accessories and positioning spring; and the 1. lamp shell stand is mainly composed of annular--shaped shell and an U shaped stand part, the height of space between the U bridge of the device and the annular shell is designed for the installing for the bulb and catoptric lagging,the buckle sets on the ring of annular shell is designed to fit with the button on the lagging, and there is another positioning spring on the bridge which is also designed for assembly purpose, but the down lights structure described above has so many defects obviously limit the application of this product which are as follow:
1. The height of space between the U bridge and the annular shell is fixed and unchangeable, and we must always assembly the bulb under the bridge, so that we could just get only the height to install the lagging and bulb, but the problem is nowadays that one has to cope with many different types of bulbs and lamp holder, for example: JC Bi-pin G6..sup.35 ,MR16 G5..sup.3, ES GU10, E10. . . etc, so the conclusion is that the old down lights structure which with the only installation height for bulb is not good enough for different environment, at least there must be some new type down lights which with adjustable installation height for bulb in order to fit different requirements,
2. The height of space between the U bridge and the annular shell is fixed and unchangeable, so we have only one position for bulb,and therefore there is no way to adjust the focus of bulb light.
3. The lamp-shell stand of old down lights showed in FIG. 1 have usually an opening for heat ventilation, in other words, this means the most part of bulb will expose after one finishes the lamp assembly, and it is very dangerous because the bulb will get higher and higher in temperature when in use, the halogen bulbs especially, so the damage would be serious if there is some dirt or inflammable articles which happen to fall on the bulb when the lamp is in use,so the producers must cover a tube-shaped part on the down lights structure to keep safety, but the designation and installation of this tube-shaped part always needs additional work.